The objective of this grant is to study the prevalence of bacteriuria in a cohort of former school children (in Calvin Kunin's original study) and a paired control group who had no bacteriuria. Each group is carefully followed by urine cultures every three months and has periodic cystograms, intravenous urograms, renal function tests and measurement of blood pressure. This first six months has been used to set up the study by contracting 457 people. So far 56 people have been studied.